Remove all_map_indices from task_state_store.clear() in context

[amoghrajesh]

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Was generative AI tooling used to co-author this PR?

• Yes - claude sonnet 4.6

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What

task_state_store.clear(all_map_indices=True) was exposed on the context object available inside running tasks. Mapped tasks run concurrently, so any sibling that writes after the clear survives it and the result is unpredictable and impossible to reason about if you go down a debugging path as to why it's not cleared :). There is no practical use case for this inside a running task: the only candidate is of a designated "leader" index doing post-fleet cleanup which would require polling sibling state, which is not available on the context object.

Current behaviour

A task could call task_state_store.clear(all_map_indices=True) to attempt a fleet-wide wipe of state for all map indices of the task. Due to concurrent execution, the outcome could have a race condition and unreliable.

Proposed change

Remove all_map_indices from TaskStateStore.clear() in the task context, and also remove out the entire plumbing: the field on ClearTaskStateStore comms message, the supervisor forwarding, the client query param, and the execution API route query param.

The flag is preserved at the backend and core API layer - external callers (UI, CLI) acting on a completed task group can still wipe all indices cleanly via the core API.

Alternative

If you need to clear state across all map indices of a mapped task group, do it from a downstream task using the CLI / core API which supports it.

Changes of Note

The removal touches the full stack from context to wire: context.py, comms.py, supervisor.py, client.py, and the execution API route. The Core API route and MetastoreStateBackend are intentionally untouched.

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[amoghrajesh]

Failures are unrelated, merging.